1. FIELD
The subject invention is in the field of filters used for removing particles from liquid flowing through the filters. More particularly it is in the field of filters intended for use with liquids in which ferromagnetic particles are entrained or suspended, such as the lubricating oil in internal combustion engines. Such particles are worn off the ferromagnetic parts of the engine during use and entrained in the lubricating liquid. The filters commonly used in the lubrication systems of internal combustion engines capture some of the particles and thus prevent them from possibly causing further wearing of the lubricated parts but it is well known in the art that filters able to capture the particles at the small end of the size range of such particles by filtering action are too cumbersome and expensive to be commercially successful. It is known to be possible to capture the smaller ferromagnetic particles by placing magnetic components in the filters as shown in the known prior art to the subject invention.
2. PRIOR ART.
Filters incorporating magnetic elements for the purpose of capturing ferromagnetic particles too small to be captured by the filtering elements are shown in the following patents:
______________________________________ U.S. Pat. Nos. British 2,014,800 2,980,257 557,214 2,838,179 3,840,045 2,860,787 4,450,075 German 4,629,558 478,770 ______________________________________
None of the prior art apparatus for removing small ferromagnetic particles from lubricating oil are known to be commercially successful. One of the primary reasons for this lack of success is believed to be that the cost of the filters incorporating the magnetic means could not be justified in terms of tangible evidence of the economic benefits of using them. Therefore, the problem leading to the subject invention was provision of filtering apparatus which effectively captures small ferromagnetic particles in liquids and which does so at less cost than the known prior art apparatus provided for that purpose. Accordingly it is an objective of the subject invention to provide apparatus for capturing ferromagnetic particles in liquids, the cost of using such apparatus to be minimal. It is evident from the following descriptions that the cost minimization is achieved in part because the apparatus is reusable, being transferable from filter to filter and therefore a second objective of the subject invention is that it be separable from the filter apparatus with which it is used and repeatedly reusable on other filters.